ABSTRACT
Pipelines, railroads, and communication cables (PRC) are nonelectrical utility systems that often share the right-of-way (ROW) with power lines. This is because of several reasons such as the restraints imposed by private and governmental agencies on the routing and the environmental impact of the PRC. These restrictions are more severe near urban areas. The sharing of the ROW raises concerns regarding the induced voltage on the PRC due to mainly three variables:
1. Electric “eld or capacitive coupling 2. Magnetic “eld or inductive coupling 3. Ground current
The level of voltage induced on the PRC depends on several factors, including the following:
• Proximity of the PRC to the power line • Voltage and current levels of the power line • Duration for which the PRC is in parallel with the power line • Insulation status of the PRC and its corrosion condition • Ground resistance of the PRC • Magnitude of the ground current
The majority of the safety problems are associated with the dielectric coating pipelines and ungrounded rail tracks. This is because the conductive parts of the PRC are isolated from the ground potential and thus retain the charges acquired from power lines. This results in elevated potential of the metallic parts of the PRC.
